ci(trais.yml): Changed release script with npm run

Changed release script from npx to npm run

Author: keviveks

.travis.yml

@@ -2,7 +2,6 @@ language: node_js
 
 node_js:
   - 8
-  - 6
 
 install:
   - npm install
@@ -22,4 +21,4 @@ jobs:
         provider: script
         skip_cleanup: true
         script:
-          - npx semantic-release
+          - npm run semantic-release